First Scan 1.6 FSI Petrol EPC on

T

tnpali01

Member
EPC Light on intermittently...

Disconnected and Reconnected Battery - no obvious change

Scan results

First Scan Engine Electronics
P1031 Intake Manifold Runner Control Valve Target value not reached
P1504 Air Intake System Leak detected
P1639 throttle Pedal position sensor 1/2 implausible signal


P1504 >>>> Had a look around engine bay with engine off and also running . Cannot see anything obviously leaking, unplugged or split ,
P1639 >>>>throttle pedal too looks ok. have seen a reset process mentioned ,

Should I clear codes as a start and see what reappears or should I address each code in turn and is there any that should be looked at first?
 
I'm not sure its the correct proceedure but i always clear the codes, take the car for a drive, and then rescan.
I'm running a Proboost ECU which makes P1031 go away . Worth searching on the forum for proboost and decide if thats the way you want to go. A2steve is your man for purchasing these.
 
The air intake leak will most likely be a poor fitting oil filler cap. There's a vacuum that runs off it to just before the maf sensor. Will cause bad running if it's not all secure.

P1639 is likely to be an old code stored when the battery has been disconnected in the past.
 
One thing worth asking regarding apparent air leaks. For the past 3 years, we've had no end of recurrent issues with reported apparent manifold air pressure sensors / air leaks etc. on our AUA and I am a firm proponent of ensuring that the oil cap seals correctly (as well as other obvious caps such as the coolant expansion tank and fuel tank cap) for this reason. Our lambda sensor (non-original) was replaced 3 weeks ago with an NGK/NTK proper one as I believed it was causing some of the underlying issues (there were sporadic lambda heater earthing errors, usually around the time of the worst misbehaviour with other lights / revving issues). Since then driving it as a daily I've not had a single air leak / MAP sensor implausible error even once - for the first time in the 4 years of having the car. If a lambda is playing silly games with the fuel mixture, can this be interpreted by the ECU as a fluctuation of intake air with the above errors resulting?
 
A2Steve said:
The air intake leak will most likely be a poor fitting oil filler cap. There's a vacuum that runs off it to just before the maf sensor. Will cause bad running if it's not all secure.

P1639 is likely to be an old code stored when the battery has been disclearconnected in the past.
Click to expand...
Yes, clear the codes, and have a drive, but it's very unlikely that the P1031 will clear, or if it does it'll be back, along with, (or should be, unless the scallys have been at work), the EML lamp, by the end of your drive. There's loads of info on A2OC about P1031, start with a read here
Mac.
Link corrected in post 8.
 
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PlasticMac said:
Yes, clear the codes, and have a drive, but it's very unlikely that the P1031 will clear, or if it does it'll be back, along with, (or should be, unless the scallys have been at work), the EML lamp, by the end of your drive. There's loads of info on A2OC about P1031, start with a read here
Mac.
Click to expand...
Hi Mac,

Did you really mean this link? - Andy
 
Thanks everyone, I'll clear the codes tomorrow and have a good read through the information you've directed me to, I'll check the oil cap, should I order a new one regardless to rule that out?
 
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